The journal, Conservation Evidence

Our online journal publishes research, monitoring results and case studies on the effects of conservation interventions. All papers include some monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. It includes interventions such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, and education or integrated conservation development programmes, from anywhere around the world.

A volume is created each year with peer-reviewed papers published throughout the year. We now accept Short Communications as well as standard papers.

Special issues contain new papers on a specific topic.

Virtual collections collate papers published in the journal on specific topics such as management of particular groups of species.

To search for papers on a specific topic within the journal select Advanced search, enter your keyword(s) and within the Source box type: "conservation evidence". This will take you to a list of actions that contain Conservation Evidence papers. In order to see the list of individual Conservation Evidence papers on the topic, please click on 'You can also search Individual Studies' at the top of this page.

Volume 13

Amphibians face an extinction crisis. Hundreds of species may be lost as conservation scientists and practitioners struggle to identify remedies to poorly understood declines spanning several decades. Due to various life history characteristics and a range of drivers, amphibians continue to be especially hard-hit, more so than any other vertebrate group. In this special issue of Conservation Evidence, studies that report the effectiveness of amphibian conservation interventions are presented to add to the rapidly growing body of literature on this topic. We here summarise the current understanding of global amphibian declines to highlight the importance of applying evidence-based strategies to amphibian conservation.

Crawfish frogs Lithobates areolatus inhabit the tallgrass prairie of the southeastern Great Plains and Mississippi Delta, and have recently been considered for US federal listing under the Endangered Species Act. Here we attempt to determine the feasibility of head-starting crawfish frog tadpoles, and establish captive-rearing protocols. Captive-rearing produced more juveniles from fewer egg masses than a natural wetland in each year from 2013–2015, and survivorship of captive-reared tadpoles exceeded that of wild tadpoles. However, high rates of malformations, partial cannibalism, disease, and predation were seen among frogs in some years, and we therefore refined protocols to reduce these issues.

The spread of non-native invasive species is among the factors thought to be responsible for the recent global declines in amphibian populations. In a Protected Natural Area of Local Interest in Tuscany, Italy, we tested approaches for preserving the local amphibian populations threatened by the presence of the red swamp crayfish Procambarus clarkii. The construction of artificial breeding ponds, with suitable vertical barriers, was initially effective in preventing the spread of the red swamp crayfish and created a source site for amphibians, in particular newt species. Unfortunately, five years after construction, the breeding sites were colonized by fish and crayfish, possibly due to the actions of members of the public.

In Denmark, nature conservation in the middle of the twentieth century mainly involved protecting areas by legal declarations forbidding the destruction or degradation of the protected area. During the period 1946 to 1969, 22 sites with fire-bellied toads Bombina bombina were protected as single ponds, and 40 ponds with Bombina were protected as a part of larger protected landscapes. We evaluate the survival of Bombina populations in these protected ponds compared to 51 control ponds where Bombina was recorded in 1940-1955, but which were not protected. In all cases, survival of Bombina was low, and although protection may have delayed extinction, there is no clear evidence that it prevented extinction. There was a trend for better outcomes in the larger protected landscapes, but this may have been due to other causes, such as more cattle grazing. It is concluded that passive protection (legal protection without active management) is not effective, whereas the type of active approach that has been used increasingly since 1982 is more promising.

We monitored 100 artificial nests of four different designs to examine the occupancy and breeding success of predatory birds in nest site limited, steppe habitat of central Mongolia. Three species, upland buzzard Buteo hemilasius, common raven Corvus corax and saker falcon Falco cherrug occupied artificial nests in all years and their number increased over the five-year study period, when the number of breeding predatory birds rose from 0 to 64 pairs in our 324 km2 study area. The number of breeding pairs of saker falcons increased at a faster rate than ravens, reflecting their social dominance. Saker falcons and common ravens preferred to breed inside closed-box artificial nests with a roof, whereas upland buzzards preferred open-top nests. For saker falcons nest survival was higher in closed nests than open nests but there was no significant difference in laying date, clutch size and brood size in relation to nest design. This study demonstrates that whilst nest boxes can increase breeding populations in nest site limited habitats, nest design may also influence occupancy rates and breeding productivity of the species utilizing them. Careful consideration is needed in designing nests to maximize occupancy rates and productivity.

Translocation of great crested newt eggs was undertaken for nature conservation purposes, with the aim of establishing a new population in a currently unoccupied part of their natural range in UK. Research prior to undertaking the translocation established that suitable habitat existed at the receptor site and no great crested newts were present at the time. Approximately 600 eggs were carefully introduced to the receptor pond from a donor pond each spring for three years. Five years after the initial translocation, a population appeared to be established, with breeding recorded in the receptor pond and two adjacent ponds. The methodology may have implications for population translocations undertaken for mitigation purposes under licence in UK, as currently the focus is on welfare and translocation of terrestrial juveniles and adults rather than eggs and larvae. Results reported here indicate that to increase likelihood of success when attempting to translocate populations of great crested newt, an emphasis on translocation of eggs as well as adults in terrestrial phase would be prudent.

Land at Ranscombe Farm Reserve showed a build-up of biennial and perennial plants following a number years of conservation management for rare arable plants. The impacts of two different forms of cultivation were compared in order to understand how cultivation might be used to control this build-up, while maintaining the habitat for the rare arable plants for which the site is important. It was found that, in comparison with minimum tillage, ploughing produced lower overall plant cover but had no significant impact on the numbers of annual plant species, or on the number or population size of rare annual plant species. Plants considered to be problem species, such as creeping thistle Cirsium arvense and perennial sowthistle Sonchus arvensis, were not affected by the type of cultivation, but the abundance of these species did not appear to have a negative impact on those annual arable plants of conservation concern.

Rat eradication resulted in prolonged presence of the anticoagulant rodenticide brodifacoum in exposed lizards, likely significantly contributing to the deaths of secondarily exposed raptors up to at least 773 days after bait application.

Crassula helmsii (Australian swamp stonecrop or New Zealand pygmyweed) was first recorded growing on Mile Cross Marsh in Norwich, Norfolk, UK before 2003. Previous management undertaken to prevent the spread of this plant across the site had been unsuccessful. A three-phase project was undertaken in 2012 to control C. helmsii on Mile Cross Marsh. The aim was to eradicate C. helmsii from two infected ponds and reduce the risk of plants spreading through the boundary onto Sweetbriar Marsh Site of Special Scientific Interest. The control programme included herbicide application and in situ burial due to the high level of pond infestation. The project successfully achieved its aim of eradicating C. helmsii from the infected ponds and preventing the further spread of C. helmsii on Mile Cross Marsh. However additional work will be required to fully eradicate the plant from the site.

This study evaluates the factors affecting community mangrove restoration at nine sites in eight different coastal villages of Manus Island, Papua New Guinea. Between June 2012 and April 2014, more than 8,400 mangrove seedlings of five species were planted on both restoration sites and sites with no history of mangroves. The timing of the plantings was uncontrolled, and some communities continued haphazard planting between the two periods. The success rate was highly variable and after 22 months the percentage of established plants ranged between 0 and 102%. My findings showed that the choice of genus planted, protection from wave action and the substrate were critical factors in reestablishment. Survival was highest for Rhizophora spp, at sites protected from wave action, and at locations with sand and gravel substrates. These results suggest that mangrove replanting success on Manus Island can be improved by preselecting sites and restricting plantings to Rhizophora spp.

We monitored five-year changes in the vegetation of 31 hay meadows under an agri-environment scheme in Wallonia, Southern Belgium. Management included delayed mowing (in July) and fertilizer prohibition. It resulted in increasing cover of characteristic forbs (such as Leucanthemum vulgare, Lotus corniculatus, Centaurea jacea) and oligotrophic grasses (Avenula pubescens, Festuca rubra), while the competitive grasses, such as Holcus lanatus, Phleum pratense and Alopecurus pratensis, tended to decrease. We interpreted this as a vegetation shift from typical hay meadow to oligotrophic grasslands due to soil impoverishment following the current management. Both habitats are of conservation value. Despite these changes in the meadow plant communities, only one of the four criteria used by the Walloon administration to indicate hay meadow conservation status changed significantly over the six-year period. This was a decrease in the cover of species indicating high grazing intensity. The number and cover of characteristic plant species, and the cover of nitrophilous species, did not change significantly.

An integrated approach was proposed for the conservation of the bee pollinators of the locally rare plant dittany Dictamnus albus. Based on previous studies that revealed the most efficient pollinators, we performed three related actions to improve their presence in the area: (i) we provided artificial nests for bumblebees and solitary bees; (ii) we added bee plants to support local populations of pollinators throughout their life cycle, and (iii) we reared and released bumblebee colonies from wild queens collected in the area. Artificial nests were occupied at high rates by cavity nesting species such as mason bees, leafcutter bees and carpenter bees, while we did not observe any ground nesting bees. Artificial nests for bumblebees did not attract any wild queens. The bee plants established at different rates: transplanted adult individuals survived better than seeds directly sown at the site. In three consecutive years we reared and released several colonies of buff-tailed bumblebees, which survived through the flowering season but only one developed new gynes.

The pine marten Martes martes is a woodland specialist that favours above-ground arboreal den sites to rest and breed in. Sheltered, elevated den sites are particularly crucial for meeting the needs of breeding females and a scarcity of suitable sites may be a critical constraint upon pine marten populations. An artificial den box for pine martens was designed and 50 boxes were installed in part of Galloway Forest, south-west Scotland, in order to (a) increase the availability and diversity of suitable den sites for breeding female martens and (b) aid monitoring of the marten population. The boxes were monitored for signs of use once per year. A proportion of the boxes was occupied by martens every year and the boxes were used by breeding females to raise their young. The den boxes can be implemented as a habitat enhancement and conservation tool, particularly in commercial forests, and used to monitor marten populations and breeding success. We recommend that conservation programmes for pine martens should consider the installation of den boxes as a habitat enhancement and monitoring tool.

The critically endangered hooded grebe Podiceps gallardoi has suffered a population reduction of 80% in the last 25 years. Although climatic conditions are suggested to be important causes of this decline, invasive species are also having a large impact. Hooded grebes have the lowest recruitment rate within the Podicepodiformes, but this is usually compensated by high adult survival. Considering these life history traits and threats, we designed the ‘colony guardian programme’, which aimed to protect nesting grebes by reducing the negative impacts of American mink and kelp gull on breeding colonies of grebes in central-western Santa Cruz Province, Argentina. Over five breeding seasons between 2011 and 2015, 10 colonies were protected using a total of 755 fieldwork days. Colonies guarded throughout the breeding season had higher recruitment (0.64 juveniles/breeding pair) than colonies with little or no protection (0.39 juveniles/breeding pair).

The black-vented shearwater Puffinus opisthomelas is endemic to Mexico and is currently listed as Near Threatened by the IUCN Red List. Ninety-five percent of the world population of the species breeds on a single island in Mexico, Isla Natividad. In 2014 a metal fence was placed on the perimeter of the island landfill site to prevent wind-blown garbage dispersal. The fence was close to the black-vented shearwater colony and we found 116 shearwater carcasses during our first survey in the area. Using thermal cameras, we assessed the harm caused by the fence to the bird population as between six and seven birds/night. After discussion with local stakeholders the fence was removed in April 2016. Since then no more carcasses of black-vented shearwaters were found in the area. These results demonstrate that such structures can have dramatic effects on the survival of nocturnal seabirds and should be avoided, particularly in the vicinity of colonies. This was an example of positive collaboration with the local community and the application of research results to reserve management.

Beach evening primrose Oenothera drummondii is a perennial plant native to the southern USA and adjacent parts of Mexico that invades coastal habitats in several countries. There are currently no accepted control methods. We conducted a seven-month controlled field trial using the glyphosate herbicide Roundup® Ultra Plus in the Odiel Marsh Nature Reserve, Huelva Province, southern Spain. Different herbicide concentrations were tested by knapsack spraying. We estimated the costs of treating an entire invaded nature reserve in southern Spain where O. drummondii has invaded 123 ha of land. A dose of 20 g active ingredient/litre was the minimum effective dose for this species in coastal dunes. As new seedlings appeared after a single herbicide treatment, periodic treatments would be necessary to maintain the population level below an impact threshold. However, the total glyphosate input (710 kg active ingredient/year) to the Reserve for an indefinite period may give rise to social rejection, and demands for the assessment of ecotoxicological impact on native fauna, adjacent habitats and site uses before initiating control actions at full scale. The control costs of the entire 123 ha invaded area for two herbicide applications/year were estimated at €162,000/year (€1,317/ha/year). This includes materials (30% of total costs) and workers (70% of total costs). The study highlights the difficulties and constraints of controlling advanced stages of invasions.

This study describes a modified mowing regime that allowed green-winged orchids Anacamptis morio, discovered in 1985 on coastal grassland on a rifle range on the Sefton Coast, Merseyside, to flower and set seed. A delay in spring/summer mowing until 15 July each year led to a progressive increase in the population to a total of nearly 32,000 flower spikes by 2016, while adjacent ranges managed by regular mowing showed no such increase.

High conservation value grasslands, which are usually marginal and agriculturally poor, are often difficult to manage appropriately for biodiversity enhancement. A key management tool for this is conservation grazing, by which grazing intensity, timing and duration can be altered to suppress certain plant species, such as the more dominant grasses without impacting on other less competitive herbaceous ones. It has been suggested that the application of molasses to plant leaves could effectively encourage livestock to consume old and rank pasture grasses. This study assessed whether such an approach could be adapted to UK conservation grasslands, by using molasses to target grazing towards problem areas of dominant grass species. When Dexter cattle were exposed to areas of upright brome Bromopsis erecta and wood false-brome Brachypodium sylvaticum that had received a single application of molasses in the autumn period, no preference was shown for the treated plants. In the late winter period, however, cattle showed a significant preference for upright brome plants that had received two applications of molasses. Therefore, if consideration is given to the timing and frequency of molasses applied to target vegetation, it can be used as a conservation grazing management tool for some less palatable grasses.

Habitat loss and fragmentation have negative impacts on the environment, reducing the habitat available to species. In order to minimize these effects we need strategies to enhance the value of refuge areas. Bromeliads are important microhabitats for many taxa during certain stages of their life cycles, and can potentially be readily transplanted. In this study we transplanted terrestrial bromeliads to test their capacity to survive the transplantation procedure over time, and assess whether they are able to maintain their arthropod communities. The experiment was performed between two Atlantic Forest fragments with bromeliads of the genus Hohenbergia. We transplanted 66 plants and monitored them over three years. We assessed plant survival and reproduction as measures of transplantation success, and made comparisons among arthropod communities to evaluate faunal maintenance post-transplantation. All the bromeliads survived the transplantation over the four-year study and conserved their arthropod community. Therefore we recommend this technique as a method for enhancing the value of fragmented habitats, because it both maintains the bromeliad fauna and aids conservation of endangered bromeliads species in the face of environmental change.

The online, peer-reviewed journal Conservation Evidence publishes research, monitoring results and case studies on the effects of conservation interventions. All papers include some monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. It includes interventions such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, and education or integrated conservation development programmes, from anywhere around the world.

The journal does not include studies solely reporting on monitoring methods, species ecology or threats to biodiversity.